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What are the reasons for an installed engine to produce less thrust than an uninstalled engine?
Is this only due to the various flight conditions encoutered during operation, such as side winds and turbulence, or are there other reasons? Also, is interference between fuselage and power plant involved?

No, these losses are well known and are called installation losses.
Their reasons are:

Intake losses. In a ground test the engine will be fitted with a screen to avoid foreign object damage, but none of the long intake tubes which are common especially in supersonic aircraft.
Generator loads: The engine drives generators to supply the aircraft with electricity. This can be simulated in a ground run, but often the generator load is higher in flight.
Bleed air: Some of the compressed air inside the engine is piped to a heat exchanger and then into the cabin for pressurization and heating, or used for leading edge de-icing. Again, this can be simulated in the static test but sometimes bleed air losses are higher in flight.

Interference between fuselage and power plant is only to be expected with fuselage-mounted engines. This can be both beneficial (as in the precompression at high angle of attack and speed on the Rafale or the F-16), or it can distort the flow when side-mounted intakes are operated at a high sideslip angle.

Also keep in mind that such losses don't help "sell" the engine to customers, and also prevent apples-to-apples comparisons, so manufacturers have a vested interest in having the highest test thrust. It's up to the aircraft manufacturer to determine what other loads they may be applying and how that will affect the actual thrust.

And on a lot of commercial aircraft, many of those losses are optional, in the sense that if you really need max thrust, it is possible to use the APU to provide bleed and generator loads.

@Harper That's not really true, I don't think.  You can't design the aircraft around not expecting those loads or your APU essentially becomes a PU and you'll need a backup for it.  If the APU dies, you're on one engine, and the other can't keep you flying and provide bleed air and generator power then you're in rather serious trouble.  I may be wrong, but I don't think you'll find many commercial aircraft designed that way.

@J... I don't think we're on the same page.  We seem to be trying to talk about different things.

@Harper I guess what I mean is that, on any aircraft, you should never need thrust beyond the system design. Surely, you can always switch the generator and bleed loads to the APU to get more thrust from the main engines, but you should never need to, even in an emergency, I don't think. From a design perspective, you have to design to the true thrust available after discounting those "optional" loads - you can't rely on them being optional because they really aren't.  You need bleed air, you need electrical power; and you need the APU to actually be a backup for those.

@J...  Are you not familiar with a bleeds-off takeoff? It is a normal procedure for most if not all large transport aircraft today, and fairly routine. If the APU is deferred, you can depart unpressurized, and start pressurizing shortly after takeoff.

@RalphJ I'm not, and I've learned something - thanks!  I'd imagine, though, that the aircraft could still safely take off in those circumstances with bleeds on.  Most of the time you're not taking off at maximum thrust anyway, generally, simply to reduce fuel consumption and engine wear.  I guess I was taking particular exception to the notion of "if you ever need maximum thrust" - it's not a question of need, this is just a measure for economy, I think.  I was taking need to mean a case where the aircraft cannot perform unless bleed and generators are off.

@RalphJ In any case, I'm happy to accept the statement that if you ever want that performance or want that economy, then the option is there, but for the aircraft to routinely need that performance would be an unacceptably risky design.

Static thrust is quite more than in-flight thrust, because the efficiency of any thrust generating engine or propeller is directly related to the incoming flow.
If there's no inflow, the accelerated air will generate more thrust. If there's inflow on the other hand, the thrust will be lower. Non installed engines are doing a simpler work.


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How widely accepted and used is the International Standard Atmosphere?
Is it used in the US as well for an example, where there is the US Standard Atmosphere. With different standard models, how widely is the International Standard Atmosphere applicable? Or is it only used in Europe, and some countries outside of it?
Appreciate your feedback.

Used in what context @GuhaGubin? Weather? Navigation? Flight planning? Aircraft performance?

In most aviation contexts, the International Standard Atmosphere is used universally. This includes things like developing aircraft performance charts, weather forecasts, and flight planning. All flying rules and other aviation standards are all based on ISA.
There are several atmospheric standards. However, for the most part, all of these standards are the same up to about 32km altitude. Since most airliner traffic occurs between about 10km and 20km, there is no need to reference different standards in different locales.
The International Standards Organization (ISO) publishes the atmospheric standard as ISO 2533:1975.  Sometimes this is referred to as the ISO Standard Atmosphere, which would have the same ISA initialization.  However, when used in textbooks, performance charts, flight planning, etc., the term ISA is always understood to mean "International Standard Atmosphere". For the rest of this answer, assume ISA to mean International Standard Atmosphere.
ISA is also an initialization of one of the other standards: ICAO Standard Atmosphere, published by the ICAO in Document 7488/3. The ICAO standard was first published following the 1950 ICAO Council, and underwent multiple changes over the years. in 1979, the Council approved the re-calculation of the data tables to align with the ISO standard of 1975. Once this was complete, the ICAO Standard Atmosphere and the ISA were identical. The ICAO document states that, "any future revisions of the ICAO Standard Atmosphere will be subject of the coordination of the two bodies [ICAO and ISO]".
Because these two standards are the same, AND also have the same initialization of ISA, AND aviation standards world-wide are driven by ICAO, there are frequent mis-uses of the term ISA within the aviation world as being the ICAO standard. However, when used in the application of aviation "things", like calculating True Air Speed, knowing whether the temperature at an altitude is + or - from ISA; it is the International Standard Atmosphere that is meant by ISA.

Absolutely exellent. Couldn't have asked for a better clarification. Thanks alot Jimmy!

I've never heard of US Standard Atmosphere.

Yes, the US Standard Atmosphere is one of the most used of the dozen or so published atmospheric standards.

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What is compressibility drag?
I don't mean wave drag here. What is compressibility drag, which is understood to be a form of miscellaneous drag?

Are you asking about when the air "stacks up" as the aircraft tries to push it, the air getting "thicker" and causing more drag? Or are you asking about something else?

This description of yours about a drag increase due to air compression brings light to the matter. That may be it. I found compressibility drag as a subcategory of miscellaneous drag and was curious as to what that was...since wave drag was classified separately in zero lift drag as well as in drag due to lift; both these concepts are clear to me. Just compressibility drag was a doubt. Could you explain further if there is anything else interesting about it.

A far as I could find, compressibilty drag is wave drag. It makes sense that it is a part of both the zero lift drag and induced drag.

@Orbit, yes, that is what I thought as well. Turns out, it is categorized separately & hence, it means something else. I get a feeling that Ron Beyer is right, but would appreciate it if someone could confirm this.

There are two cases of drag and both are bundled into the term wave drag. One is from lift creation without leading edge thrust (normal force on the structure pointing slightly backwards due to angle of attack) and drag from the change in thickness along the flow path, causing overpressure on surfaces pointing forward and suction on surfaces pointing backward.

Let's do a Gedankenexperiment:
Think of air streaming around a body as flowing inside a stack of flexible tubes. The walls of the tubes are impenetrable, infinitesimally thin and follow the local streamlines faithfully. When the body approaches at subsonic speed, the air in the tubes near that body makes way for it by speeding up: This reduces the needed cross section and lowers static pressure, so the total pressure will stay constant. On the back side of the body the air slows down again and the tubes regain their old cross section and static pressure. Bernoulli in action.
When the speed nears the speed of sound, however, the speeding up is joined by a drop in density. Still, the air near the body speeds up but that will not change the cross section as much as before, because now this speed increase is coupled with a loss of density. The cross section still drops, but not by as much as before. More tubes have to bend away from the body and need the air in them to speed up so the body can squeeze through. More general: A change in body thickness (more precisely: The second derivation of its cross section according to flow direction) will work on more tubes, so its effects do not die down as quickly as in subsonic speed as you move away from the body orthogonally to the direction of flow.
At the speed of sound the cross section decrease due to speed changes is exactly balanced by the drop in density, so the same mass of air needs more volume and eats up all the gain from increased speed. Now there is a wall of air which cannot yield facing the approaching body. That is the sound barrier. In reality, the speed around that body does not reach the speed of sound at the same station in all tubes, so there are mildly sub- and supersonic sections which will allow it to squeeze through. Still, drag is much increased and depends heavily on details in the body contour.
At supersonic speed density changes more than speed, so in order to reduce its cross section, the air in the tubes will slow down in order to make way for the body. Since it has no advance warning of the approaching body, it does so in a shock. As a consequence, the cross section of the stream tube can now be reduced because density increases in that slower air past the shock. Static pressure increases also so total pressure can stay constant again. The drag coefficient drops with further increasing Mach number because the density change becomes dominant, allowing the body to squeeze through the air more easily.
This thought experiment was explained in 1951 to researchers at NACA Langley by Adolf Busemann. One person in the audience, a young fellow named Richard Whitcomb, used the insight he gained to formulate the area rule a few weeks later.

So would you call this wave or compressibility drag?

@Daniel: Wave drag is not dying down as speed increases above Mach 1, being caused by the local inclination of the structure. The drag described here is proportional to the second derivative of cross section over the direction of flow, and it peaks around Mach 1. But the boundaries are fuzzy, I admit. It comes down to how you define wave drag precisely and what fraction of the total drag is then called wave drag.

Yeah, right. Some people might say that this is called both wave and compressibility drag. But as I showed in my answer, some might say that this is only wave drag, and compressibility drag is something different.

@PeterKämpf: Wave drag could happen anywhere where a shock results. It need not be where a local inclination occurs. It could be on the smooth surface of an airfoil, where the accelearation is so high that Mach 1 is reached, causing a shock. The adverse pressure gradients and the flow separation that may result is wave drag. Area rule supposedly lowers wave drag (as I have learnt it; however, how it does so isn't very clear to me). Your explanation sheds light on this and implies that area rule reduces compressibility drag and not wave drag. Is this what you mean? Appreciate your feedback.

@Guha.Gubin: No. The shocks in subsonic flow cause mostly pressure drag from separation. This is definitely no wave drag, because here a compression shock results (indirectly) in suction. Wave drag is also pressure drag, but caused by overpressure on forward-facing rsp. suction at rear facing surfaces due to compression shocks rsp. expansion fans in supersonic flow. And yes, the area rule is for reducing compressibility drag.

Could you explain why the drop in density causes that the cross section is not changed as much as before? Because for me it sounds counterintuitive (lower density -> lower "amount" of air so it is easier for a body to makes a way through it).

@Konrad The amount of air that passes through the streamtube per unit of time does not change, but due to lower density it takes up a larger volume at higher Mach.

One more question, why does speeding up is joined by a drop in air density as the air nears the speed of sound?

@Konrad That can be shown with the ideal gas law and the law of conservation of momentum, but not in a comment.

I added a new question :)
https://aviation.stackexchange.com/questions/94617/why-does-when-the-speed-nears-the-speed-of-sound-the-speeding-up-is-joined-by-a

@Konrad I answered a new question :)

Tbh I still cannot understand it, please help me out. I understand that when closing to the LSS speeding up is accompanied by a drop in density, streamtubes crossection is not decreased as much as before, etc.; that is clear. But what happens at Mach 1, I mean what happens to the crossection of streamtubes: is it reduces or not, and if not how it is possible for the body to pass through? The phrase „drop in density eats all the gains from increasing speed” is not clear for me.

@Konrad When Mach = $\sqrt\gamma$ streamtubes will neither expand or contract with changs in pressure / speed / density. That is why people spoke of a sound barrier. That airplanes still can squeeze through is due to the fact that speed is not the same all around them - some air is faster and will slow down in order to make way, some is slower and speeds up. In all cases the changes in cross section are small and many stream tubes are afflicted - hence the drag maximum close to Mach 1.2.

Compressibility drag is a type of parasite drag caused by the compression of air ahead of an aircraft traveling at high speed. An aircraft not designed for supersonic flight will experience it as it approaches Mach 1. The effects are noticeable once the aircraft reaches a Mach number of 0.6 to 0.7 and the coefficient of drag rises by 0.005. In subsonic aircraft design it is also considered the limit of normal economic operation of the aircraft.

however, this sounds like wave drag.

The way I understand it, wave drag is not compressibility drag, it is a component of drag that presents itself due to compressibility drag.

Unfortunately, the definition of these two terms is not consistent across literature. Often, they are both used to describe the same effect: the increase in drag due to the presence of shockwaves.
However, sometimes a differentiation is made between the terms, depending on the way that the total drag is decomposed. You may find that compressibility drag is used to describe the increase in drag due to an increase in mach number at constant lift (thus a composition into zero-lift, lift-dependent and compressibility drag), whereas wave drag is used for the drag which is "physically" caused by the presence of shock waves.
In that case, the values can differ. Take for instance a certain flight condition at transonic speed and increase your angle of attack while keeping your mach number constant. Compressibility drag (according to this definition) then stays constant, whereas wave drag will increase. Check out the following document for some more clarification: http://mail.tku.edu.tw/095980/drag.pdf

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Boundary layer momentum thickness
Could someone please explain the concept of the boundary layer momentum thickness and its difference to boundary layer thickness calculation? Some explanation about the application of the boundary layer momentum thickness is also much appreciated.
Thank you in advance.

See here. Warning: the math is gnarly. :)  https://www.slideshare.net/Haroonmechno/fm2-35616441

Both are different ways to express the boundary layer thickness in a deterministic way.
The boundary layer according to wikipedia:

a boundary layer is an important concept and refers to the layer of fluid in the immediate vicinity of a bounding surface where the effects of viscosity are significant.

Since there can be debate about what significant means, multiple formulations for the boundary layer thickness exist. And depending on the problem to solve, one of them can be more suitable than the other.
Therefore the boundary layer thickness is by typically specified as the distance where the velocity reaches 99% of the free stream velocity.
The boundary layer momentum thickness can be exactly specified as the distance a uniform flow field should be displaced by to equal the total momentum flux (m*v)*v of the real boundary layer (non-uniform).
There is also the boundary layer displacement thickness, comparing the mass flux deficit (m*v) rather than the momentum flux deficit (m*v)*v, as highlighted by the slides in Juan Jimenez's comment.
Take a look at this quora answer as it contains good explanatory figures.
Update:
I found a paper with comparative figures of the displacement and momentum thickness based on XFOIL results. It's worth to take a look at. Iliev, Sergiu. (2016). Aerofoil Analysis using XFOIL - Practical Implementation for Preliminary Wing Design. 10.13140/RG.2.2.30861.54243.
An example of where displacement and momentum thicknesses are useful can be found in the XFOIL documentation.
The displacement thickness can be used to couple a boundary layer solver with a potential flow solver (ISES code).
XFOIL uses the momentum thickness to calculate the viscous drag.

Viscous Formulation
The boundary layers and wake are described with a two-equation lagged
  dissipation integral BL formulation and an envelope e^n transition
  criterion, both taken from the transonic analysis/design ISES code.
  The entire viscous solution (boundary layers and wake) is strongly
  interacted with the incompressible potential flow via the surface
  transpiration model (the alternative displacement body model is used
  in ISES).  This permits proper calculation of limited separation regions.
  The drag is determined from the wake momentum thickness far downstream.
  A special treatment is used for a blunt trailing edge which fairly
  accurately accounts for base drag.

Thank you for the answer. But shouldn't the values for b.l momentum thickness and b.l displacement thickness be the same? Perhaps there could be a small difference between the calculated b.l thickness and the other two, since it accounts for a 99% freestream velocity attainment.

Good question. The displacement boundary layer actually compares the mass flux being m*v, while the momentum boundary layer compares the momentum flux (m*v)*v. I'll update my answer to correct for this.


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Is there a benefit to representing a SID/STAR in 3D?
There are several examples of 2D representations of SIDs and STARs on the web.  I have yet to encounter a 3D representation of one.
Does one currently exist?  Are there any benefits of representing a SID/STAR in 3D as opposed to 2D?

Controllers and pilots are used to converting 2D charts into "3D images" in their head. It is very simple for people who are used to doing it every day. Introducing a whole new chart type on the other hand would likely require the users to spend a lot of extra mental capacity on processing information that they are used to being presented in another way.

I have flown aircraft with Augmented Enhanced Reality built into their PFDs. They represent a desired flight path on the PFD with a rectangle whose unit of measure is dependent on the phase of flight. For example purposes, you would see a box on the PFD roughly 200 feet high by half a mile wide with 1 to 5 miles between each box in the enroute phase of flight. Your goal is to fly through each box. There is a dot or crosshair target on the screen to represent your actual current flight path based on trend vectors and statistics like airspeed, ground track, vertical speed, and rate of turn. Keeping the target centered in the boxes will keep you on your flight plan entered into the system. I have seen this system in Garmin and Dynon equipped aircraft.
Flight Directors and autopilots with Flight Directors can give you visual cues for pitch and bank corrections based on your programmed flight plan and actual flight vectors.
Also, apps such as Foreflight will graph out your entire flight plan including instrument procedures in virtual reality. It will then allow you to virtually fly the plan in 3D for preflight planning.
I don’t find this last resource useful in actual flight. Any other tablet based 3D representation would be just as bad. A simple piece of paper would be preferable in actual IFR flight. Any technology that would increase pilot workload any further than it already is in IMC would be dangerous. More than a couple of seconds to look at the information you need clearly displayed would be too long. The current charts facilitate rapid information retrieval by using standardized formats for every chart. There is no need to fiddle with gadgets unnecessarily.
One way this can be very useful is for at home training. Get a few pictures as large as possible taped under your tv or monitor. Have all of your charts, sectionals, and checklists applicable to a real, normal flight out and ready. Then, chairfly the entire flight from preflight planning to hangaring the aircraft in detail. Play the 3D virtual reality representation of the flight on your tv or monitor when it comes time for the flight phase.
By the way, your standard ILS or GPS approach in a linked standard six-pack already represents the information in 3D. You just have to be able to interpret it as such.

Important advantage of paper maps is also that they won't run out of batteries or randomly fail.


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What does it mean when a track "straddles north"?
Have heard a couple controllers taking note of a track that "straddles north".  What do they mean?
According to Google, the definition of the verb straddle is to extend across or be situated on both sides of.  Cannot see how this would relate to a track.

Some context would probably be useful: can you add some information about where/when you heard this?

Desired track is 002 degrees. Wind is from 270 (don't worry about true/magnetic for now.) A Piper Cub has a heading somewhere west of north to maintain a track of 002.  Is this the straddling you are referring to?

So the problem is that cruising altitudes are assigned based on heading E or W. If the desired track is within a few degrees of north or south, the heading needed to maintain the track could 'straddle' north or south. With some tracks/wind combinations two aircraft flying the identical route at different airspeeds could fall into opposite hemispheres. Traffic in the reverse direction has the same issue, possibly resulting in opposing traffic at the same altitude. So which altitude do you assign/use?

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Can wing clouds caused by a high angle of attack be recreated in a lab? Also, why doesn't this work for smaller wings (e.g. r/c planes)

Can this be recreated in a lab? Any equations would be helpful if so. Also, why doesn't this happen during high angles of attack on a smaller wing, such as that of an R/C plane?

If the lab is inside a wind tunnel, yes.

This water comes from condensation of water vapor already in air after pressure is decreased suddenly due to lift mechanism, and temperature is decreased accordingly. Air must be near water saturation (near 100% humidity ratio). The value obtained with small wings at small speed cannot produce the pressure change required to lower temperature below the due point. See this general explanation. Which "equation" are you looking for?

related: https://aviation.stackexchange.com/q/14327/1467

@mins  I believe you mean to say 'dew point'.

The sudden fog due to the fast (and hence adiabatic) expansion of air is re-created, in many laboratories, in the simple cloud chamber.
For those that haven't seen one (they are fast disappearing from school labs due to 'radiation risk'): it is a small, usually round chamber with a window. Inside, there's a a small amount of water to ensure a water-vapor saturated air. As the chamber is closed, the water is in stable equilibrium with its vapor. The chamber is connected to a hand pump that resembles a bicycle pump, but working in reverse. When you pull the pump handle, you make a partial vacuum in the chamber, and due to the sudden descent in pressure, the temperature drops too, and some of the water vapor inside the chamber condenses. If the pull is light enough, the condensation will take place only along the trajectory of the alpha- or beta particles emitted by a suitable source placed inside. But if you pull hard enough, the whole chamber fills with fog.

As an addition to @xxavier's excellent answer: RC planes have far lower wing loadings, so the pressure difference between ambient and over wing pressure in case of model airplanes is far too small to cause that massive condensation seen in the photo above.
The pressure coefficient on the top side of a model airplane wing will rarely drop below -1 (except for a very pointy suction peak at high angle of attack) while the pressure coefficient on the top side of an airliner wing with slotted flaps extended can be as low as -2.5. Next, the dynamic pressure (which is needed to convert the pressure coefficient to an absolute pressure) is orders of magnitude higher for airliners than for model airplanes.

Typical airliner pressure distribution in landing configuration (picture source). For comparison, a model airplane distribution can be found in the linked answer.

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In air return flight?
Ok, we had a few beer.
Imaging a plane with two cockpits back to back. One Pilot flies to the destination and the other returns without turning the plane.
The question is, whether there is a profile for a wing that would create lift in both directions. Our idea was a wave form.
Is there a profile for a wing with a reverse gear?

All wing profiles provide reverse lift as well, with drag that is a lot higher though. The problem is, what will you do with the horizontal & vertical tail?

Don't forget solutions for not doubling the engines, not inverting the angle of the swept wings, not exchanging high-lift devices between edges; and solutions to block ailerons, elevators and rudder on the now leading side, to switch active end-wheel, invert air intake/exhaust for APU and air conditioning... more beers could help :-)


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Why are aircraft tires not pre-spun prior to landing?
Currently, as far as I know, most modern (big) airliners do not pre-spint the tires before landing. The question is why not, as there are certain benefits. This question was asked here before Why are aircraft tires not pre-spun prior to landing to preserve them? , but I think not all benefits were mentioned there, especially not the passenger comfort.
Advantages: From most important to less:

Comfort: At the moment of touch down, the gears are fiercely slammed backwards. The passengers won't experience this any more, which ads up to their complete flight experience.
Safety: A slipping wheel has no grip, also not sideways. Also the aircraft will be more stable at the moment of touch down (see 1). When it does not work, we are just back to the currently accepted old situation. Even when it fails in the sense that the tires spin too fast!
Tires last longer: This saves money for replacing them and the saves the time to do so. Most delays I personally experienced by interim maintenance on aircrafts were by maintenance that consisted of one tire replacement only! Still most tire wear does not come from the touch down moments.

Disadvantages: From most important to less:

Costs: Of course it will come with a price and add extra weight to the aircraft, etcetera.
Control: The gyroscopic effect of spinning wheels have their influence on the behavior of the aircraft. But this problem is already there just after takeoff. Would an A380 pilot really notice?? Or is it a minor issue at takeoff that would be a major one at landings? Please tell me!
More difficult tire maintenance scheme: For each tire a log needs to be maintained of how many times the tire touched down where the system was both working and not working.

Design considerations: The system can take the time from when the gear is completely down to touch down to spin-up the tires. It is not a problem when the tires' speeds to not exactly match each other or the landing speed.
Simple implementation: Attach an electric motor to each axle of the main gears. At take-off they are disconnected, otherwise they would act as dynamic breaks. At landings they always just operate at full capacity. The size and power of these engines need just be enough to overcome slightly more than the resistance of the axle itself and should be just at the level that, after a minute, the tires keep spinning at an average landing speed (and don't speed up any more). For the (tire maintenance) logs each axle also should have a detection for if it is spinning above a certain speed, like faster than half the average landing speed.
What is the decisive reason something like this was never implemented on a modern (big) jet aircraft?

I already mentioned " Why are aircraft tires not pre-spun prior to landing to preserve them?" as a duplicate. It is already answered but still does not satisfy me completely.

The question is much longer, but the answer is the same: when engineers put numbers (i.e. $) to these sorts of proposals, the cost is virtually always far greater than the benefits.  VTC as duplicate.


text:
How do you determine the lift coefficient of a finite wing using the coefficient of an infinite one?
How assuming I know the lift coefficient of an airfoil/infinite wing, how do I then use this value to calculate the lift coefficient of a finite wing? Please quote your sources.
Many thanks,


text:
Can commercial pilot get paid for introductory flights with their own customers?
Can a pilot with their commercial certificate look for their own customers, rent an airplane, and get paid to do introductory flights?
If yes, where in the FARs does it talk about it?

The problem is probably going to be the "rent an airplane" part, and as you describe it, I highly doubt it. Typically "introductory flights" are done by a CFI at a flight school for some discounted rate which is basically a half-hour to an hour of flying and a half-hour of ground (and the customer sits in the right seat), what you are talking about sounds like giving a lesson being a non-CFI, which again, I doubt the FAA would look kindly on.

What exactly do you mean by an "introductory flight"?

There are three parts to your question and the answer to all three is no. And there isn’t one specific place in the FARs that says you can’t do this, but reading Parts 91 and 135 along with appropriate ACs and Legal Opinions of the FAA leads most pilots to realize that they can’t do this.
§91.147   Passenger carrying flights for compensation or hire. contains a list of requirements that you must satisfy as well.
If you look for customers it is considered 'holding out' and according to AC 120-12A ‘A carrier becomes a common carrier when it "holds itself out" to the public, or to a segment of the public, as willing to furnish transportation within the limits of its facilities to any person who wants it.’ And if you are a common carrier, then for this type of operation, you must have a Part 135 certificate.
As a commercial pilot, you can be paid to fly someone in their airplane. Lots of commercial pilots do this. However, if you provide the plane then you are acting as a Part 135 operation and you can’t do it.
Getting paid is also not allowed. Since you can‘t do parts one and two of your question, you are acting under your Private Pilot certificate for the flight. At most, you can split the immediate expenses i.e. fuel, landing fees, etc. Even that is a bit dicey since you won’t have a ‘common purpose’ with the person you are flying. In other words, without holding out for customers, you wouldn’t have been making the flight anyway.
Not part of the question, but there are lots of things you can do with a commercial pilot’s license:
Corporate Pilot, Charter Pilot, Contract Pilot (for a private owner), Freight/Cargo Pilot, Ferry Pilot, Banner towing Pilot, Sight-Seeing/Tour Pilot, Agricultural Pilot/Crop Duster, Skydiver Pilot, Photographer Pilot, Airshow Pilot, Demo Pilot (aircraft sales), Medical Evacuation Pilot, Humanitarian/Charity Pilot, News/Traffic Pilot, Pipeline Patrol Pilot, National Defense or Border Patrol Pilot, Firefighting or Forestry Pilot.

You might want to mention part 119 too: it defines when you need a 135/121 operating certificate and when you don't. It also lists the activities that are exempt from 135/121, i.e. the things you can do with only a part 61 commercial certificate.

Excellent answer, but...  Where in the CFRs does it specify that if a commercial pilot provides the aircraft he/she needs a pert 135 operating certificate?  My understanding is that private carriage for compensation in a personal aircraft is permitted.  Regarding splitting the costs as a private pilot:  Here I don't think the CFRs specify how a private pilot is allowed to find passengers interested in sharing costs.  There is a clear distinction for commercial pilots, but no "holding out" verbiage limiting PPLs from making new friends.

@MichaelHall Where in the Part 91 or Part 61 does it say you are allowed to carry passengers for hire? Other for flying for charity compensation isn’t mentioned. It does say you may share expenses on pro rata basis. So you need to dig into Part 135/121/119 and Legal Interpretations and Certificate Actions to find out the regulations.  tldr; Carrying passengers for compensation in your own aircraft (even with a commercial certificate) is strictly forbidden unless you are Part 135.

@JScarry, CFR 61.133(a)(1) "A person who holds a commercial pilot certificate may act as pilot in command of an aircraft -
(i) Carrying persons or property for compensation or hire, provided the person is qualified in accordance with this part and with the applicable parts of this chapter that apply to the operation; and
(ii) For compensation or hire, provided the person is qualified in accordance with this part and with the applicable parts of this chapter that apply to the operation."

Please show me where it says a commercial pilot is limited to sharing expenses on a pro-rata basis, and where it specifically prohibits exercising commercial privileges (private carriage!) in a personally owned aircraft.

@MichaelHall You have it backwards, show me where it says that you are allowed to do it. You can’t show me because it is not allowed. Unlike some regulations, this isn’t even ambiguous. You may not provide the plane and pilot for hire unless you are operating under Part 135.

I gave you the reference above.  If it isn't even ambiguous then please offer a counter.  It is apparent to me that what is "backwards" is a basic philosophical difference:  "If something is NOT specifically prohibited, it is by default permitted" versus "if something is NOT specifically permitted, it is by default prohibited."  I cannot provide a reference where the FAA specifically says a commercial pilot is allowed to furnish a personal aircraft for private carriage, but apparently neither can you provide a reference specifically prohibiting it.  So there we are...  Does anybody else know?

P.S.  To clarify, the holding out aspect of this question is crystal clear - if you are aggressive in seeking customers and/or let it be known you are giving rides for a fee you are holding out and will run afoul of the FAA.  My position, (until proven wrong) is that private carriage in a personal aircraft is not specifically prohibited, and therefore is allowed.

P.P.S.  Back to the original question, I'm pretty sure the FBO renting the airplane would not allow you to perform commercial operations in their aircraft.

Depends.  If the commercial pilot in question is not a Certified Flight Instructor, he/she cannot sign off on dual instruction time for a student pilot and said student pilot cannot log that flight time in their logbook. - see FAR 61.181-189.
Now if a commercial pilot appropriately rated for the category and class of aircraft, or with a type rating, with a current Class I or Class II Medical certificate takes a passenger up for compensation or hire on an introductory flight, they may do so.  But it cannot count for instruction time.

I don't think this is accurate because not only does the pilot need to be rated for the type of aircraft, but the aircraft may need to be maintained to Part 135, Part 91, etc, depending on the operation involved. See this question which means you possibly also need to be operating under an operators certificate as well... Just having a commercial doesn't mean you can charge for your time.


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Why do you need airplane mode on a device for a plane trip?
I'm about to take a plane trip to my dads house but I'm just curious why you must have airplane mode on?
I'm no aviation master here, just looking for information.

To avoid interfering with aircraft systems.

Can Bluetooth and wifi still be used? Airplane mode disables cellular connection.

No, WiFi and Bluetooth both use transmitters. Airplane mode means airplane mode and switches off all to the phones' radios.

@Simon Airplane mode still allows GPS and Wifi reception, at least on some models.

@JonathanWalters GPS is receive only.  WiFi can't work without transmitting since it must negotiate with the access point and acknowledge network data recevied.  You may be confused with some other function but there is not such thing as "receive only" WiFi.

@Simon I didn't say that the WiFi works in some sort of receive only mode. I said it works in airplane mode. I have experienced this with multiple phone manufacturers and models. I am using WiFi to post this comment while in airplane mode.

@JonathanWalters That's a serious flaw.  WiFi should be disabled.  What phone are you using?  The whole point of airplane mode is that the transceivers are turned off.  You can manually enabled WiFi afterwards, but that violates airplane mode.

@Simon This works for me as well when I switch to airplane mode (which at first turns off any transmission) and then selectively turn WiFi on again. Then I have airplane-mode minus WiFi, i.e. WiFi works, but nothing else. I have a Moto G1 if that helps, but I'd expect other phones to behave similar when I explicitely override AP mode.

@PerlDuck Since you are now using a transmitter, you should check with the operator if it's lawful or not.

@Simon My experience mirrors that of PerlDuck: airplane mode initially turns off Bluetooth and WiFi, each of which can be subsequently enabled and used whilst in airplane mode. This has been my experience with two different generations of Samsung Galaxy and a Moto X. I will further point out that the US airlines that instruct passengers to use phones only in airplane mode also advertise and encourage use of the in-flight WiFi.

@Simon I don't think the operator has sth. to do with or can influence the behaviour of a phone I bought at amazon. But I confess that I (as a pax) have once turned on GPS in-flight to see how fast we travel. I was surprised it worked (given the metallic tube the cabin finally is). I thought of Faraday and didn't expect GPS to work.

Anyway I got off the plane thx guys

Yes, @Piggyuniform, sorry. We were getting off-topic. Hope you don't mind.

In addition, there was wifi and I had Bluetooth headphones, to sum it up, airplane mode does disable both bluetooth and wifi, but they can be enabled, this means that you are bypassing airplane mode, but AP mode is still blocking cellular service ;)


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Drone swarm technology on missiles
since drone swarm technology can control large amounts of drones in a coordinated manner, could it also be used on missiles? Imagine an aircraft could launch a few swarms of small missiles (like a itano circus/macross missile massacre), each swarm could "box in" multiple enemy planes from a few directions and spray the area with shrapnel. The missiles don't have to be big and have large fuel tank and it would be guided by the radars on EACH member of the swarm and on the aircraft itself. Would this system be a practical dogfight weapon?(assuming the aircraft could carry this weapon syetem without decreasing its aerodynamics)

"Could it be used on missiles?"  As soon as someone actually puts in the work to do it.   Ideas do not implement themselves.  Since you came up with the idea, I nominate you to sit at an engineering work bench for the next 8 years and make this happen.

AA missiles are already a swarm of hot metal scraps the instant it detonates

http://gizmodo.com/watch-fighter-jets-poop-a-swarm-of-tiny-screaming-dron-1791021392

I disagree with the closing: even if the answer is true about AA missiles, it could have been interested to mention cruise or antiship missiles, that uses (I think about Soviet designs notably) swarm technologies to coordinate their attack

NO
Missiles are the size they are so they can carry the warhead all the way from the launcher to the target.  The warhead is designed to be "just big enough" to destroy the target, but no larger.  (Adding just a little bit of unnecessary weight to the warhead/payload of a rocket massively increases the amount of fuel required to maintain the same performance, thanks to the Rocket Equation)
If you want to replace a single missile with 10 "mini-missiles", you'd find the effective range of those missiles would be unacceptably low.  Furthermore, the mini-bombs that you'd fit on the mini-missiles might scratch the paint on the target but likely would not pose much of a threat, even in a swarm environment.
Think of it another way - it's really easy to defend against 500 pounds of bees (wear a bee suit).  It's a lot harder to defend yourself against an angry 500 pound bear.


text:
ADS-B receiver, dongle vs SBS-3 or Garmin
Is there any differences between FlightAware Pro Stick USB and Kinetic SBS-3 or Garmin for aircraft tracking purpose?
Something like: SBS-3 can receive twice more data.. is there any benefits?
Assume, that I have power PC.

Are those all ADS-B Receiver setups that you are using on the ground? I've never heard of them, do you have links?

https://flightaware.com/adsb/prostick/  http://www.wimo.com/sbs-3-virtual-radar_e.html  If Garmin has  a ground station, I am not able to find it.

something like this: http://www.modesbeast.com/radarcape.html or https://airspy.com/   does they have benefit against dongle? I need only 1090Mhz

I imagine harware in some form is needed no matter what, between the ADS-B Antenna and your PC, as your PC will not have the radio tuning/signal decoding needed to interpret the data that the planes are sending out.  Read reviews, see what others are saying about their performance.  I have a Garmin ADS-B In/Out transponder in my plane, and just watch stuff on FlightRadar from time to time at home.  I gather folks use equipment such as you show to collect data at home and perhaps send it to FlightRadar and similar sites.

Waht is your use case? What do you need as an output from the receiver.

I want tracking the airplanes on the ground, in case of dongle I can use dump1090 i.e. For other hardware there are other soft.
My question mostly about hardware, how to choose good hardware and why some parameters matters, like ADC

Most ADS-B receivers in the market (including USB sticks such FlightAware Pro Stick USB) are receiving the same data using the standardized GDL-90 protocol. There is not a lot of data available on their amplifier characteristics.
Both in the air and on the ground, the main differenciator will be the quality of the antenna and its positioning. In that respect, avoid some USB sticks with a tiny embedded antenna without an antenna connector, as they will lead to lower performances than those of devices that are connected to much more efficient antenna.
Furthermore, with any device with an antenna connector, you will be able if needed to install the antenna at a more convenient location, as it is important the antenna has unobstructed view of the sky and when installed the ground be located as high as possible. According Garmin GLD-5x installation manual, ADS-B receiver antenna should be a standard 50 Ω vertically polarized antenna with a VSWR < 1.7:1 at 978 MHz and < 1.5:1 at 1090 MHz.
On that respect, the FlightAware Pro Stick USB, Kinetic SBS-3 and Garmin GDL-5x are all supplied with an external antenna connector, so I guess the cheapest one will do the job.


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why do wings have high aspect ratios on commercial airliners?
On the Boeing 777x they have made the wing span large to increase area and therefore lift. why don't they change the aspect ratio so that the wings don't have to be that long but maintain the same area and therefore lift? this would mean there is no need for the hinge and therefore less complex. Wouldn't this also mean the wings are less of a lever so less force so their could be lighter (proportionally less strong) joint to the plane? To be clear I am not talking about a blende wing body. The wing would be no thicker than normal. Is there a name for this?

Aerodynamically, you want the aspect ratio to be as high as it can be (for a given wing area). You want infinite wingspan, because that results in no induced drag. But that is not very practical at airports, and a bit heavy.
Structurally, you want short stubby wings because they have a very low bending moment. In fact structurally, you want zero wing span. But that is not very practical at take-off time.
As always, aerodynamic desirability implies structural objections, and vice versa. The aerodynamicists need to strike a deal with the structures engineers: a balance needs to be found. As long a wing span as possible, with as thick a profile as possible, using a material that is as light as possible. So a long wingspan is desirable and is only limited by structural constraints: as you say, at a certain point the longer wing span's increased weight will offset any aerodynamic advantages.
In aluminium, the optimum was reached over the course of a few decades. But now there is a new material with a better strength/weight ratio: composite carbon fibre. Carbon is much stronger than aluminium, and it is woven in a matrix of resin, with most wires running in the direction of highest stress. With carbon fibre, even the direction of material strength can be optimised. And the B787 and A350 have even higher aspect ratios than the B777.


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Which busy commercial airports have a very large GA operation attached?
I was thinking about OAKland International, and how the General Aviation side of the field is much larger than the commercial side, but the commercial side is still very significant.   How many others are there like that?
I don't mean the many GA fields that get occasional visits from a "United Express" or "Delta Connection" rubberband turboprop.  Let's say the criteria are

Commercial and GA operate on separate "sides" of the airport, e.g. Most commercial traffic uses one area and runway(s) and most GA traffic uses another area and runway(s). Not John Wayne/Irvine.
They are physically connected by taxiways, not separate airports.
The commercial side serves over 100 flights a day of A318/B735 or larger (so not Long Beach or Billy Bishop), and is big enough to be a hub airport for a network like Southwest or Ryanair.
the GA side doesn't necessarily dominate over the commercial side, but it has the ground infrastructure to do so if the demand were there.

Related: Can you fly a light GA airplane into a major hub?... It's not a dupe, but some of the answers list some examples, most notably DFW (Dallas/Fort Worth).


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Flight time between Taipei - Vienna vs Vienna - Taipei
I recently took a flight between Vienna (Austria) - Taipei (Taiwan) and then back Taipei - Vienna.
The interesting thing that I don't understand is why it takes longer to fly TPE - VIE than VIE - TPE?
Vienna - Taipei - 11h40mins:
Vienna-Taipei
Taipei - Vienna - 13h 40mins (two hours longer):
Taipei-Vienna

Welcome to aviation.SE! Does this answer your question? Why do flight times differ between traveling East versus traveling West?

I see now that the pilot must have observed the wind prediction before flight - but what is interesting is the fact that flight path was also longer - he first flew at least 1000 km to the nord - and then to the west. What would happen if the pilot took shortest path to Vienna? How long would the flight be? I understand we would face then headwinds - obviously it's still better to make extra 1000 km than to face headwind?

Two Words: WINDS ALOFT

winds aloft and temporary airspace closures. Say you're not allowed to fly over a specific country for the return flight for some reason, so you need a detour.

@FrenkyB, we are talking about winds that can reach quarter of the speed of the aircraft itself. A 1000 km is just a bit over eighths of the distance. Well worth it. Also, the shortest route from Taipei to Vienna starts north-west. The eastbound flight is the one that usually makes huge detour (and is still faster with the 100 knot tailwind).


text:
Why aren't aeroplanes controlled from a control center (without a pilot inside)?
Nowadays we have space crafts that go as far as to the Mars and they are controlled by people sitting in the earth (by some remote control method).Why are aeroplanes not controlled in this way?Are pilots absolutely necessary?
Thanks for any help!!

Your first assumption is faulty.

Spacecraft are not subject to weather, traffic, crowding, congestion and scheduling delays.  There is no suitable alternate to re-route a spacecraft to; airplanes can be rerouted to alternate destinations.

Read this and you will understand and expect this will continue.

For airplanes that don't carry passengers, we already do this. In fact my country (Malaysia)'s maritime patrol fleet is being converted to drones (mostly regular planes retrofitted with long range radio control). The US is currently waging what is effectively a full-blown war/assassination program in the Middle East and Afghanistan and Pakistan using planes remotely controlled from the US. For planes that carry passengers note that even spaceships that carry passengers have pilots on board - that is a safety issue

@mins: Follow the link. The assumption that is wrong is that aeroplanes are not controlled this way

Because some of us actually enjoy flying!  IOW, commercial passenger aircraft are only a subset of all airplanes.


text:
Why don't aircraft use gimbaled engines instead of flaps?
Why do aircraft use flaps rather than vectoring the engine or angling the engine?
Elon Musk said he would gimbal the engine like a rocket with the aim of reducing total weight of the aircraft and thus increasing its range.

Aircraft have all these unnecessary things like tails and rudders and elevators - not needed. Just gimbal.. anyway.. gimbal the electric fan. For some weird reason gimbaling motors is normal in rockets and not in aircraft. Why not.— Elon Musk (YouTube)

It is a lot easier to move a flap or slat than the entire engine, and it works when the engines don't.

Imagine landing with one engine out.  Elon musk doesn't live in the real world.

@Greg Taylor: In fact, most of us only HAVE one engine, and that's usually at idle during landing - from short final to turning off to taxi, at least.  I can't offhand see what use movable engines or thrust vectoring would be, unless you're building a VTOL craft like the Harrier or Osprey.  And of course those are military, where things like cost & efficiency are secondary considerations.

"If all you have is a hammer..."

Historically, flaps and control surfaces were moved manually: The pilot would move a stick, a control column or pedals, and pulleys or pushrods would transfer this force to the control surfaces. To do this with engines was physically impossible.
With the introduction of hydraulics, large enough forces for tilting engines were available for the first time. Some aircraft used them, but this application did not find widespread use because the possible lift increase was smaller than what could be achieved with flaps. The same goes for controlling the aircraft: Directed thrust control forces are much smaller than what was possible already with control surfaces. Also, the responsiveness of tilting a heavy engine is much worse that that of a light control surface. Consequently, moveable engines were mostly used for short take-off and landing (STOL) applications. The Do-29 was one of several experimental aircraft which could pivot the propellers to take off at lower speed. Note that in case of the Do-29 the engines stayed in place; only the propellers and their driveshafts would move. Other designs would tilt their wing and with it the wing-mounted engines. In all those cases this was only done to enable short take-off runs, not to control the aircraft.

Do-29 in the Dornier museum (picture source)
Other applications were for special cases like flying boats:

The Dornier Do-26 could tilt the rear engines up for operation on water to reduce the impact of spray on the propellers (picture source). Note that this was not for control, but for lifting the props out of the spray area.
Control surfaces are better suited for creating control moments:

Control surfaces sit at the ends of the aircraft, so they have a much better leverage. Engines were placed close to the center to minimize the control problems caused by a loss of a single engine.
Control surfaces modify the lift force, whereas engines modify thrust, which is in the order of magnitude of drag and, consequently, an order of magnitude smaller than lift.

However, this is only true as long as aerodynamics works in a linear fashion. Which is not the case with separated flow and stalled flight surfaces. To overcome this limitation, the exhaust stream of jet engines is deflected by pivoting the nozzle (or paddles, as done on the X-31). This is much easier to do than to move the whole engine. Also, since the engine stays aligned with the airframe, the intake will continue to work and the frontal area of the airplane does not increase; both important considerations which stand against pivoting the whole engine.

Vectoring nozzles on the Sukhoi 35 (picture source)
Generally, aircraft are controlled by changing moments which in turn rotate the aircraft such that the desired flightpath change is effected by the changed aerodynamic forces. There have been attempts at direct force control, however: One Dassault-Dornier Alpha Jet was fitted with moveable wing pylons which could be rotated around a vertical axis. When moved, this would create a side force which enabled the pilot to directly shift the aircraft's flight path sideways. With moment control, you first need to roll the aircraft in order to tilt the lift vector sideways and then roll back shortly before the desired sideways change is complete. This is much harder to get right with moment control than with direct force control, especially for small corrections.

Vectored nozzles are fine, but the reason people don't gimbal the engine is because it's gyroscopically stabilized by the rotor's rotation. A lot more energy would be required, and the responsiveness would be much lower, for gimballing engines over moving flight control surfaces.

@IwillnotexistIdonotexist: Only when all spools rotate in the same direction. If the HP spool runs in the opposite direction to that of the LP spool, gyro effects will be almost eliminated. Still, when such an engine is rotated quickly (as would be required for control), the loads on the engine bearings will be punishing.

@peter kämpf Elon Musk was suggesting an electric jet and therefore could have contrarotating propellers in the engine? Would there be any problems with this?

@SRawes Quite aside from the angular momentum/gyro problem, with current-day engines jutting out forwards from the wing, deflecting it even slightly would induce a massive drag force seeking to increase the angle, eventually shearing the engine off its pylon. As mentioned by Peter, the bearings for all the moving parts in such a system would take a legendary beating, and the additional hydraulics to steer the engine would be heavy and constitute an additional failure point.


text:
Could a modified J58 jet engine be used commercially?
Could this mean for more fuel efficient supersonic commercial cruising?
If so in what ways would it need to be modified and how possible is this?

There is a lot more to supersonic cruising than just the engine...

I know but it is a part of it and the question stands @ron beyer

I would like to complement @ymb1's answer by adding that a major part of the aerodynamic drag, in the case of the Concorde, was due to the generation of its massive shock wave. Hence, the relative inefficiency despite having highly efficient engines.
Commercial operation usually calls for larger aircraft in order to benefit from economies of scale. But larger aircraft also generate powerful shock waves that we have yet to deal with.
I would recommend reading the following paper for addition information on the subject
History and economics of, and prospect for, commercial supersonic transport

"Commercial operation usually calls for larger aircraft in order to benefit from economies of scale." That's an over-simplification. Sales of the A380 are super-sluggish, for example.

And the scaling laws mean it's not actually true. Larger aircraft have more absolute drag, but the drag-to-payload ratio (which is what actually matters) might easily be better.


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Why do we have to manually tune VOR receivers?
As the VOR frequency is automatically selected when the DME is selected, under what system conditions is manual tuning of the VOR required?
(aviation-safety-bureau.com)

"As the VOR frequency is automatically selected when the DME" Not in my plane it isn't, unless you are talking about the DME being colocated with the VOR. There are many VOR's to choose from, not all of which have DME. You need to choose the frequency of the one you want to navigate based on.

How is manual tuning of a VOR can be carried out from the aircraft VHF NAV control panel  ?

On my aircraft you either use a knob on the NAV radio to select the standby frequency then hit the "flip-flop" button to move it over to active, or I have a Garmin G430W which I can tune NAV1 by selecting a menu and VOR then hitting the flip-flop button. This is pretty typical in most aircraft.

Sir it seems to me that you are flying small aircraft, what about a320 how would you tune the VOR ?

"when the DME is selected". This sounds confusing to me.Where do you select the DME exactelly ?

As pointed out in the comments, I think you have things turned around. If you select the frequency of a VOR that has a co-located DME, the system will automatically also select the DME frequency. Thus, I'm guessing that what you perhaps meant to ask is under what conditions do you manually tune the DME frequency. If that is NOT what you are asking, put a comment after this answer to that effect, and I will delete this answer.
Now, if that is what you are asking, the answer in one sense is "never" in that, at least in civilian aircraft, you always select the VOR frequency. However, prior to my retirement in 1999 there were a few, very few as I remember, facilities that provided DME but at which there was no co-located VOR. To get the DME, you selected the VOR frequency that would have been paired with the DME had there been a co-located VOR. and it was the frequency of that non-existent VOR that was shown on the charts along with a clear and obvious note that there was no actual VOR. I have no idea whether in our current airspace system such still facilities exist.
You can find the standard VOR-DME frequency pairings here (PDF) or read about it on Wikipedia.

HLE NDB / DME has a collocated NDB and DME.  There is no VOR.  There are several NDB / DME stations around.  One reason to tune the DME without an operational localizer / VOR.  https://skyvector.com/?ll=43.40459850833437,-114.2392730672357&chart=301&zoom=1

I take it ILS/DME pairings work like their VOR/DME brethren?

@UnrecognizedFallingObject, yes. The same receiver is used for both ILS and VOR (though the decoding is different) and the pairing works the same.


text:
Why was the Iraqi airspace closed on 12 Mar 2020?
I was onboard BA105 on March 12, 2020 (London LHR to Dubai DXB), which was rerouted (I hope this is the correct term) to fly over Egypt. See the inflight map photo below:

Close to arrival, the crew informed us that we had changed course because of an Iraqi airspace closure, bit didn't give any additional info.
How would I find out more details about what happened (I couldn't find anything through a basic online search)?

This may have some relation to it

The real question: did you get the extra airmiles credited properly for your detour?


text:
What is GPS HIL in layman's terms?
GNSS Horizontal Integrity Limit/ Horizontal Protection Level is a measure of GNSS position error/integrity that's very important in RNP operations and RAIM, but it has an obtuse definition in aviation regulations like DO-229D that's hard to apply in practice:

[HPL] describes the region assured to contain the indicated horizontal position. It is a horizontal region where the missed alert and false alert requirements are met for the chosen set of satellites when autonomous fault detection is used.

Is there a simpler definition that is equivalent for most equipment? It seems like a 1 - 10-X% accuracy bound, given pessimistic assumptions about satellite availability, but given the description it's hard to be sure?

The true position of an aircraft in flight can be measured, but the accuracy of any measurement is limited. The actual measured position is the actual true position plus the actual measurement error. Each error of position measurement is 3dimensional. If observed over a long time, the distribution of the errors will have a shape and size that is characteristic for the measurement method.
For GNSS receivers, the measurement of the latitude and longitude measurements depend on each other, while the vertical measurement of altitude does not correlate much with the horizontal measurement. This is why the usual model to describe is a cylinder:

Image source: ESA
The Horizontal Protection Level (HPL) is simply a horizontal cut through the cylinder where the aircraft is located with an acceptable level of probability.
The cross section of a cylinder is a circle, and the radius of this circle is the horizontal performance requirement.
The HPL is just a geometric definition. It is useless without acceptance levels and performance requirements, which are not part of its definition. Those emerge from the performance of an GNSS augmentation system like WAAS for GPS or EGNOS for Galileo, and the requirements for the use in aviation. Here below is a table of GNSS augmentation performance requirements by FAA for different phases of flight:

Image source: ICAO

So does the HIL/HPL signal output by an aviation-grade GPS receiver change based on the performance requirements?  That seems to be what's suggested in your answer.

@CodyP I don't think I wrote that. HIL/HPL are geometric figures. They are pointless without performance requirements, but they do not change depending on the actual requirements. Which sentence do you find wrong or confusing? Maybe I can change something.

Sorry for the confusion and thanks for the help.  The thing that's unclear to me is what the "acceptable level of probability" and "accptance levels and performance requirements" are, and why if its something simple like 1-2x10^-7 per approach it isn't stated more prominently.

No worries! I am not aware if or how navigation units handle actual performance requirements. The figures in the table, like the 1-2x10^-7 (=99.99998%) per approach are just arbitrary trade-offs between feasibility, cost, and acceptable risk. At least that is my limited understanding. I would be happy if there was another answer that could shed more light on this aspect, or maybe it is worth a dedicated question.


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What is the difference between placing wheel chocks on the outer wheels as opposed to the inner wheels of the main landing gear?
Recently I am aware of a change made to the IATA Ground Operations Manual (IGOM) in regards to the position of the wheel chock on the main landing gear.

Is there a justification for why one method is preferred or is safer than the other?

Just a guess: Easier to see and therefore harder to forget if they are on the outer wheels.

Or perhaps, the ground crew doesn't have to walk in front of or behind un-chocked wheels before inserting or after removing the chocks? Typically more headroom outboard of the gear compared with inboard? Better visibility to know that they are installed? Any or all of the above?

I note that the comments are based on the assumption that the new rules indicate chocking the outer wheel. Can you confirm that's the rule now

In the 4th edition (2015) the outer wheels were chocked, and from the list of changes, it seems it changed in 7th ed. (2017).

If the inner wheels are chocked, the ground crew person would likely have to place their arm/hand in the path of the wheels to grab the rope and pick up the chock.


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Do any regulatory bodies require ISO 9001 QMS certification from airlines or service providers?
As the aviation industry is transitioning to SMS approach, is having ISO 9001 certification required from any civil aviation authority? Similar to how IATA requires IOSA certification and certain airline /  airport authorities require ISAGO certification for ground handling companies. Note this question is not trying to debate the advantages or disadvantages of ISO 9001 certification towards achieving safety, but rather the presence or non-presence in the regulatory landscape.

There are quite a few 135 companies in the United States that are transitioning to IS-BAO certification.  There are quite a few European companies that require ISO 9001 certification.  I don't think, however, the push to these standards are done by the regulatory authority but by the insurance companies.

ISO 9001 for which airline processes?

No, there are no civil aviation authorities that require QMS implementation.
ICAO documentation (Document 9859) discusses the integration of other systems, such as quality and environmental management systems. There are advantages of integrations, such as facilitating data management and reducing redundancies.
For example, a QMS has many of the same documentation requirements as an SMS, so an integrated system is logical. However, not all operator benefit from an QMS, especially the smaller ones.

This makes a lot of sense. Later on I heard anecdotally a rare case where an airport authority required ISO 9001 certification for ground handling companies, but since the official word from ICAO promotes integration probably means requiring another management system on top of an SMS is unlikely.


text:
Why don't airlines install Faraday cages in their planes?
Cell phones and other electronic devices can interfere with the pilot's comms and other crucial avionics, as well as cell towers on the ground, if the plane is low enough. Due to these issues, the FCC forbids using cell phones on planes, while the FAA allows airlines to choose when they may be used, once the plane is out of range of the ground cell towers.Source
The fact is, though, many people just don't put their phones on airplane mode. You can forbid it all you want, but without enforcing it (not feasible - too many ways to get around it), it doesn't do much.
Enter the Faraday cage.
Faraday shields are, in short, metallic surfaces that prevent the transfer of electromagnetic waves from one side to the other; Faraday cages are ones with holes in them, blocking waves of specific wavelengths while allowing all others through. You've surely seen Faraday cages before; they're in the doors of all microwaves.
This seems to be an easy (perhaps somewhat expensive) solution. Just put one up on every airplane, maybe with a wire going from one side to the other to allow the on-board Wi-Fi to still work. But it would block all outside communication, regardless of if you've got airplane mode turned on or not. If the cage is routed around/inside the sides of the planes and across the door between the cockpit and the cabin, the pilot would have no problem communicating with the outside world.
I feel like I'm overlooking something obvious, but I can't put my finger on it. Is there a hole (so to speak) in this theory?

Cross-posted from Travel.SE.

An airplane cabin already has something like a Faraday cage around it: the fuselage skin. I wonder if radio interference from electronics is blocked by the skin and thus escapes through the windows? Making the cabin into a full Faraday cage would probably mean putting wire mesh over all the windows.

@mins I’m not sure I understand.

@Sanchises Not necessarily. Treated glass can be a Faraday shield - see the pictures in the linked Wikipedia article.

Welcome to aviation.SE! I think @mins means, why would you want a Faraday cage in an aircraft in the first place? We have a lot of "why don't..." questions on this site, and the answer is inevitably some variation on "too heavy/expensive/inconvenient compared to the benefit". We've already established that using phones on board is not a serious aviation issue (at least in the US), so it isn't clear what problem you think this would solve.

Material used on Boeing planes when the fuselage and nacelles are built from carbon fiber instead of aluminum. The shielding is already there. Without this electromagnetic protection we would have serious problems with lightning strikes in flight.

An aluminum airframe is basically a Faraday Cage, which is why metal aircraft are frequently struck by lightning and survive with little or no damage to the airframe or systems.

The holes in Faraday cages don't block "specific frequencies, allowing all others through". They block wavelengths greater than the hole sizes, thus all frequencies below the threshold. IOW, they form a high-pass filter, not a notch filter. But the wavelength of WiFi is down to a few centimeter.

Cell phones and other electronic devices can interfere with the pilot's comms and other crucial avionics

As far as I can tell, nobody ever demonstrated an actual case of this. At least as long as the electronic device is FCC compliant, but all the consumer electronics has to be.
Keep in mind that all the avionic systems already have to be shielded against interference originating outside the aircraft and this shielding works for that in the cabin too.

Due to these issues, the FCC forbids using cell phones on planes

No. It is due to the issues with the network. Moving mobile clients introduce frequency shifts due to Doppler effect and timing shifts. The system is only designed to handle them for the speeds of cars, but not much higher, so mobile client in an aircraft will not only have unreliable connection, but will also cause problems for the other clients on the ground.
In part, it is also so they don't have to explain everybody over and over why the batteries drain so quickly.

FAA allows airlines to choose when they may be used, once the plane is out of range of the ground cell towers.

The aircraft is never out of range of ground cell towers, since the range is 35 km and the cruise altitude is only 10–12 km.
FAA allows airlines to choose when they may be used as long as appropriate relay is provided so they actually do work.

without enforcing it, it doesn't do much.

As long as only effect ever actually observed is that that phone's battery quickly drains and the phone turns off anyway, nobody cares anyway.

@mins, yes. FAA and EASA both allow (see this related answer) airlines to install a cell that forwards calls via sat link and then cell phones may be used on board. Not sure how many actually do it; it's not that common in practice. However, the same rule permits installing WiFi servers and that is quite common now.

@mins, the phone also probably would work as is, but the connection would be somewhat unreliable and the battery would be draining quickly. The main reason it is forbidden is the associated load on the ground network.

@mins, yes, that's the case that is permitted. If the plane has its own cell, you may use it (subject to horrendous roaming charges, of course).

Afaik, the network problems are no longer a concern with newer wireless systems. The FCC was all prepared to lift the ban and the airlines managed to get them to continue it. I believe the airlines are citing safety concerns, but passengers are also against it. They don't want to listen to people on the phone the entire flight.

It is quite common to hear the interference from the cell phone on the sound amplifier present nearby. If there is a possibility that this "Bu-bubu-bububu" will interrupt a critical message inside the cockpit, I understand why not allowed.

@TomMcW, yes, it is actually large part of the reason. However, I think that while 3G would be relatively immune, the Doppler shift would wreak havoc in the LTE (4G) orthogonal frequency multiplex.

"since the range is 35 km and the cruise altitude is only 10–12 km." Given the radiation pattern of cell phone relays (mostly parallel to the ground), I doubt that we can compare the "horizontal" range with the height of the aircraft.

@Quentin, the range is given by timing (for GSM; CDMA and UMTS don't have hard limit; not sure what is the limit for LTE). It has nothing to do with the radiation pattern.

@JanHudec Until you take received power into account.

@Quentin, the received power is known to be sufficient at the typical cruise altitude.

A Faraday cage for the entire aircraft is not necessary. All the avionics are inside metal enclosures so they have their individual little Faraday cages. Resistance to electromagnetic interference (EMI) is part of the design, affecting not only the enclosure but the design process of the electronics themselves.

Cabling can be designed with a shield (foil or braided wire around the signal cabling), or it can be designed to reject interference (balanced signalling).
Installing a Faraday cage to isolate the passenger cabin from the avionics would only eliminate one possible noise source. Modern aircraft are full of electric systems, and each of them is a potential source of noise. So aircraft electronics have to be shielded not just from passenger phones, but from each other.
Aircraft electronics have to deal with strong sources of EMI: radar and lightning.


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Which one has a higher success rate between Infrared homing and Radar homing missiles, for air to air combat?
I know Infrared missiles don't work on long ranges, so I will keep my question limited to short ranges only, in which both missiles can work.
In such short ranges, which guidance system has more chances of success/kill in an air to air combat? Infrared homing or Radar homing?
If one can also lump in Active radar homing and Passive radar homing in his/her answer, that will be an added bonus. Thanks!

Among IR, active radar, and semi-active radar, semi-active radar definitely wins the range because you can almost use arbitrary sized aperture and transmit power using ground station, without being limited by the size and weight of the missile, which is the choice for long range missile like S-300, AIM-54, R27. IR works well in close range simple because IR has a much shorter wave length hence a larger relative aperture for the same diameter.

But it's indeed an interesting topic why there isn't IR + radio instruction homing mode isn't popular, but active radar + radio instruction is. They both share a lot of characteristics like maximum range but IR is much better close range. My guess is active radar is better head-on, which fits the interception use case better.

This topic is very broad, and there is copious material available on it. Therefore, this answer will be generalized.
IR targeting is very useful against jet engine aircraft, because there is a clearly defined thermal contrast in the thermal output of the engines. At close range it is low cost and low complexity compared to a passive radar targeting system. It is essentially, a point and shoot.
Passive radar targeting utilizes a more powerful, larger antenna on the deploying aircraft, and relies on the more powerful illumination which the targeting aircraft is capable of. If the illuminating transmitter is in the front of the deploying aircraft, then the aircraft's attitude must be maintained to continue to illuminate the target until strike.  This exposes the deploying aircraft to increased risk, and is avoided in close quarters.
Active radar targeting requires more on the missile electronics, but can work better in a point and shoot environment, and does not require the deploying aircraft to continue illumination of the target, allowing evasive maneuvers and pursuit of other threats.
The trade space between targeting methodologies is great and is dependent upon situational conditions. For example, at a long range, a passive radar targeting method can provide increased target strike assurance, and lowers the SWAP (size, weight and power) of the targeting package in the missile.
At close range, IR homing is often selected because it works well on close targets, has the best SWAP, allowing more weight for ordinance and motor.
All targeting systems have their disadvantages.  For example, while IR is very effective against jet engines, having the sun, or even glint can foil them, as can IR flares. Shooting against a ground target may not be as effective with an IR seeker, but it is done.  A passive radar seeker can be more effective against countermeasures, particularly when multi-static radar is employed.  In that case, several transmitters illuminate the target, from different aspects, and the passive receiver in the targeting unit can eliminate most countermeasures.
In the world of countermeasures, there are similarities. For example, IR Chaff is about as effective as RF Chaff, and does a good job at breaking target lock and inhibiting target acquisition.
Getting back to active radar, the SWAP is greatest for this targeting system, but it has the ability to act autonomously, similar to IR targeting. Antenna diameter is a limiting factor for good SN ratios. But this strategy is good for point and shoot, and works well at closer ranges.
With respect to kill rates, that is highly dependent upon the type of target and we haven't narrowed the discussion to aircraft vs ship vs vehicle, which influence the choice due to background radiation, reflections, etc.
The question is extremely broad, and coverage of the broad topic with multiple questions in this venue is limited.

I don't really agree active radar has great size/wieght. It's the heaviest among passive IR, semi-active radar, and radio instruction. It's not great for close range, either.

@user3528438: I don't think "greatest" was intended to mean "best", but rather "largest".

I don't like the term semi-active radar, because radar and lidar by their inherent mechanisms require active illumination of a target.  Bistatic with a passive receiver would be more accurate terminology.  With regard to the comment, higher SWAP is higher size, weight and power, and also translates normally into higher cost.  Rough rule of thumb, double the warhead targeting SWAP and that the cubed hit in cost.

Hi, FYI - I have edited the question to cater only to the air-to-air combat.

@mongo: nevertheless, semi-active is the standard term used in military aviation (and SAMs) to describe systems with external illumination.

Most semi-active (SARH) are bistatic CW systems, where the illuminator separate and distinct from the passive warhead homing device. Bistatic accurately encompasses SARH methodologies, and is the preferred terminology.

@user3528438 I am not following your comment. I don't think that I represented active radar as featuring a preferred size and weight.


text:
What is this plane, based on its wing?
Here is the picture of the wing of a plane. Does anyone know which plane it is? The flight number was AF 1834 going from Paris CDG to Berlin Tegel in november 2015. The plane was from Air France and to me it was a A321 but not 100% sure. From what I found A318, A320 and A321 where used by Air France to go to Berlin from this source.

Very likely it was an A321.
On underside of the wing you can read the top of the letters of the registration. First should be F for France, third is clearly a T. The shapes match F-GTA#, where # is either B, D or P.
These are registrations of Air France A321 aircraft.

This is an Airbus A321-111/-212 variant.
I can't second the original poster regarding the registration (though likely correct), but the underside of the wing has double-slotted flaps vs that of the single-slotted flaps on the A318/A319/A320.  You can tell based on the additional flap fairings on the trailing edge of the wing. The A321 has five flap fairings beyond the engine whereas the A320 has 3:

(image source: Airbus Aircraft Characteristics)

Welcome to Av.SE! Nice insight into the Airbus variants. Is there a schematic or drawing available on-line that depicts the different numbers/locations of the flap tracks for the different models?

@RalphJ You can see the difference in the "scaled drawings" section in the Airbus Aircraft Characteristics documents. I added a picture.

This is a great answer, I learned something new. This should be the accepted answer. Welcome to aviation.stackexchange.com.


text:
Is there a use scenario for the Detote value?
Im currently working on the fuel calculation of an airplane, when i stumbled upon a value called "Detote". When asking around, no one knew what the use case of this value is or why it even exists.
In the handbook it is described as follows:

A DET (detotalizer) fuel amount is a digital value from which the
  fuel used, as measured by the fuel flow meter, is deducted, allowing a
  comparison to be made with the measured fuel contents.

This value can be set via the UFCP and will show up on the MFD.
What are the application scenarios for the Detote value?
Did you see this value implemented on an aircraft?

"Cockpit display and control of the fuel is via a fuel quantity detotalizer,
which is a manual digital counter that indicates the fuel fed to engine, preset by maintenance to the total preflight fuel load." (source)

Welcome to aviation.SE! If I understand your handbook quote correctly, the DET fuel amount is how much fuel is left in the tanks. If so, that seems to have an obvious application :-)

Note that the existence of detotalizer was how Air Canada flight 143 could be dispatched without working fuel quantity gauge and consequently without anybody noticing less fuel was loaded than requested.

On 747-100/200 aircraft, the "detotalizer" was on the flight engineer's panel. The image below is, I believe, from a 747-400 because those on the -100/200 aircraft were mechanical digits rather than electronic, but I couldn't find an image of the earlier version.

Before engine start, the f.e. set the aircraft gross weight and the total amount of fuel. From that point, the instrument kept track of of your decreasing gross weight and fuel quantity.
The amount of fuel showing on the detotalizer was considered to be more accurate than that shown by the fuel quantity gauges, and thus was controlling for en route flight decisions.
Besides quickly and accurately giving the amount of fuel remaining in general, it was critical to redispatch operations (sometimes called reclear). See the "Reserve reduction" section of the Wikipedia article on flight planning for a detailed redispatch explanation.
Basically, though, redispatch allows you to legally get to a destination for which you can't (or don't want to) carry enough fuel to to reach that destination with the required reserve fuel. What happens is that you're dispatched to a destination short of your desired destination. Then, nearing the destination to which you were dispatched, you are then redispatched to the desired destination.
An example. I used to fly JFK to Tel Aviv, a flight that always required a redispatch in a -100 and sometimes in a -200. The flight was usually between 10 and 12 hours, depending on winds, how you hit the North Atlantic track system, and routing through Europe. Let's say the expected fuel burn was 275,000 lbs. The dispatch fuel requirement would be that plus 5% reserve (from memory, might have been a higher percentage). So, to be legally dispatched to Tel Aviv, you had to have 288,750 lbs of fuel at takeoff. But let's say the most fuel you could load (or wanted to) was 280,000 lbs.
No problem. You dispatched to Athens, well short of Tel Aviv, and for which the fuel requirement was considerably less than the 280,000 lbs you had on board. You used a route that took you over the Mediterranean on the way to Tel Aviv through an intersection abeam Athens. You had two flight plans aboard: one from JFK to Athens and one from that intersection to Tel Aviv. The fuel requirement for the second one was the burn from the intersection plus 5%. Thus the reserve fuel requirement for redispatch was 5% of something like 30,000 lbs (burn from the intersection to Tel Aviv) versus 5% of 275,000 lbs (burn from JFK to Tel Aviv).
Coming up on the intersection, you looked at the detotalizer. If it showed at least the required legal fuel on the second flight plan, you called the company and were redispatched. If it showed less, you would turn left at the intersection and refuel at Athens. As I remember, I never had to do that, although, truth be told, there was the occasional fudging of a hundred pounds or two, maybe three, but never more than that.


text:
How to convert IAS/CAS to TAS up to Mach 3?
Someone had recommended that I use this formula to convert KCAS/KIAS to KTAS:
https://www.experimentalaircraft.info/flight-planning/aircraft-navigation-speed.php
If you scroll down to "True Airspeed, TAS," you will see this formula:
=KIAS*SQRT(SEA LEVEL AIR DENSITY/AIR DENSITY OF DESIRED ALT)
So, enetered into an Excel spreadsheet cell, the formula would look like this:

=100*SQRT(1.225/0.905)
100 is the KIAS, 1.255 is air density at sea level, and 0.905 is air density at 10,000 feet.
This formula gives us 116 knots for KTAS.
This formula works for low airspeeeds, but as airspeeds get higher, the KTAS that is given is not accurate. As I have learned, this formula does not take into account "compressibility," and therefore the KTAS will not be accurate at higher airspeeds.
I am interested in a formula that I can enter into my Excel spreadsheet that will give an accurate KTAS for all airspeeds up to Mach 3, and altitudes up to 100,000 feet.
Is there one particular formula that will work?

For higher airspeeds, TAS is always calculated based on the Mach number:
$$
\mathrm{TAS} = M \cdot a_0 \sqrt{\frac{T}{T_0}}
$$
where $ a_0 $ is the speed of sound at ground level ($ a_0 \approx 661 \, \mathrm{kt} $) and $ T_0 = 288.15 \, \mathrm{K} $ is the temperature at ground level. This formula is just based on the fact that the speed of sound in air is proportional to the square-root of the temperature.
How to calculate the Mach Number
Now, we need to distinguish between subsonic and supersonic flow. The pitot tube will give you the ratio of impact pressure $ q $ and static pressure $ p $. From this ratio, you calculate the the Mach number:

subsonic flow:
$$
M = \sqrt{5 \left( (q/p)^{5/7} - 1 \right)}
$$
supersonic flow:
$$
M \approx 0.8813 \sqrt{\frac{q}{p} \left( 1 - \frac{1}{7 M^2} \right)^{5/2}}
$$
This equation needs to be solved iteratively.

The following plot shows the Mach Number as a function of the $ p / q $ ratio (red for subsonic flow, blue for supersonic flow):

Calculate the True Air Speed
Now that we have the Mach number, we need to calculate the TAS using the formula from above. The last missing piece is the static air temperature $ T $, which can be calculated from the measured total air temperature $ T_\mathrm{tot} $:
$$
T = \frac{T_\mathrm{tot}}{1 + M^2 / 5}
$$
This gives the final answer:

Unfortunately, there is no easy way to calculate this based on KIAS as an input. You will need the ratio $ q / p $ and the temperature $ T_\mathrm{tot} $ as measured by the aircraft.


text:
Is 'make small one turn' a standard phrase?
I've heard it somehow that some of USAF controllers say this. is the phrase used in real ATC? if it is, is there any other similar phrases?

I've never heard that. The closest thing I've heard is ATC request  a 360-degree turn for spacing.

Could it have been "rate one turn"? And I guess there was probably a turn direction included in the instruction; if you can recall the full instruction it might be easier to make sense of it.

Standard ICAO phraseology is " MAKE A THREE SIXTY TURN LEFT (or RIGHT) [reason] "

More standard English, at least in the U.S., would be "make one small turn", but I've never heard such a term used. Also, "small" doesn't explicitly define how much of a turn, and it doesn't indicate the direction of the turn. ATC instructions are usually precise, something like, "turn right 90 degrees for identification." I remember getting that type of instruction from controllers in setting me up for practice PAR approaches (civilian equivalent of GCA) at Kingsley Field, Klamath Falls, Oregon, U.S.A back in 1969. However, in the next 30 years of flying I never heard a like instruction, at least that I remember, for the simple reason that I never had to fly a PAR approach for real.
The abbreviations are:
PAR - Precision Approach Radar
GCA - Ground Controlled Approach

Identifying turns is a last-ditch effort to establish radar contact on an aircraft with no operative transponder and no precise position report. It's still a valid method but the percentage of planes with working transponders has probably increased quite a bit since 1969 (while the percentage of ATC radar systems that don't have secondary radar has decreased considerably as well!).


text:
How to manage anxiety just before flying?
I am new to aviation and flying.
I have a one hour trip that is making me anxious and sleepless.
How can I manage the fear and is it safe or just like the news we hear on news?

I'm voting to close this question as off-topic because it is better suited to Travel.SE

Welcome to Stack Exchange! Take a look at this on Travel.SE: Are there tips and tricks to overcome a fear of flying? Does this answer your question?

It is normal to have anxiety when experiencing something new.  These "butterflies" of the stomach are your body's reaction to your minds confusion over a new situation.
This is where training and mental discipline are key.  Rationalize what is making you uncomfortable and focus on your task.
Looking down at my landing gear while flying along at 2000 feet somehow made me more nervous, so I learned to focus on the horizon and to calm down.
Put what is bothering you aside as best you can.  With experience, your mind will differentiate and sort out what should be making you nervous (losing a wing), from what should not.  Then your body will not react (by being nervous) to normal aspects of flying (departing, cruising, landing).  Enjoy the view!

+1 for the rather heartless remark. I just don't understand the trigger happy itch to close posts among some commentators.

@curious_cat The question appears to be about flying as a passenger, rather than as a pilot (because it's a while before you get to fly solo).

Thanks Robert you've made me better.

@curious_cat: Because it's not really a question about flying.  It's a psychological question that could apply to any new experience.  Certainly I was a bit nervous the first time I rode a horse, for instance, and if I could remember that far back, probably the first time I drove a car, rode a bike, went skiing...


text:
What is the flight time from Beirut to Paris using different aircraft?
If the distance between Beirut and Paris is 1985 miles / 3194.55 km / 1724.92 nautical miles, and a flight using Airbus 320-200 take 4 hours and 40 minutes, how much would it take using the following aircraft:

Airbus 321
Airbus 330-900 neo
Boeing 787-9

And by the way what is the neo word?

There are of course various factors that play in here but lets look at base numbers

Airbus 321 Cruise Speed: 515 MPH
Airbus 330-900 Neo: no cruise data published yet
Boeing 787-9 Cruise Speed: 561 MPH
Airbus 320-200 Cruise Speed: 514 MPH

With the above listed speeds rough estimates of travel time would be

Airbus 321: 3.85 Hours
Airbus 330-900 Neo: no cruise data published yet
Boeing 787-9 Cruise Speed: 3.54 Hours
Airbus 320-200: 3.86 Hours

Lets dig in a bit, you state that the A320 takes 4 hours 40 minutes for the flight but at cruise the numbers are showing 3.86 hours. The above numbers don't account for climb out which will occur at a lower speed and you are flying west which usually means head wind. I would assume your distance number is a point to point number which does not reflect the path a given flight will actually fly. So chances are the A321 which only cruises 1MPH faster than the A320 will take the same 4:40 time. The 787-9 is a bit shy of 10% faster so it will shave about 28 minutes off the flight time if we are comparing total times on a more holistic basis.

As per your second question Neo stands for New Engine Option.

The Airbus A330neo ("neo" for "New Engine Option")